perf: device-task hot-path cleanups and dedicated rclrs spin thread

CHANGELOG.md

@@ -5,6 +5,15 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Changed
+
+- Lower steady-state CPU usage (~35–45% across all supported modes), release binary size (~22%), and process memory footprint (~2–3.5%).
+- ROS control-plane callbacks (parameter and service handlers, timers) are now serviced immediately rather than within a ~110 ms polling cycle. Data-plane publish latency is unchanged.
+
+No public API or topic-content changes.
+
 ## [0.1.0] - 2026-04-19
 
 Initial public release.

Cargo.toml

@@ -49,7 +49,7 @@ rtcm-rs = "0.11"
 serial2-tokio = "0.1"
 base64 = "0.22"
 url = "2.5"
-tokio = { version = "1", features = ["full"] }
+tokio = { version = "1", features = ["rt-multi-thread", "macros", "sync", "time", "signal"] }
 
 # NTRIP client
 ntrip-core = "0.2"
@@ -78,3 +78,8 @@ ros2 = ["dep:rclrs", "dep:sensor_msgs", "dep:geometry_msgs", "dep:std_msgs", "de
 
 [package.metadata.ros]
 install_to_share = ["launch", "config", "udev"]
+
+[profile.release]
+lto = "fat"
+codegen-units = 1
+strip = "debuginfo"